Neuroradiology Practice Questions

Q: In which of the following diseases is the NAA peak seen?

Canavan disease. ***Canavan disease*** - **Canavan disease** is a **leukodystrophy** characterized by a deficiency of the enzyme **aspartoacylase**. - This deficiency leads to an accumulation of **N-acetylaspartate (NAA)** in the brain, resulting in a significantly elevated NAA peak on **magnetic resonance spectroscopy (MRS)**. *Tuberculoma* - **Tuberculomas** are granulomatous lesions that typically show reduced or absent NAA, an elevated lipid peak, and sometimes an elevated **lactate peak** on MRS. - The metabolic profile reflects inflammation, necrosis, and cellular destruction rather than elevated NAA. *Glioblastoma* - **Glioblastoma**, a high-grade glioma, is characterized by a significantly elevated **choline** peak (reflecting increased cell membrane turnover) and often an elevated **lipid/lactate peak** (due to necrosis and anaerobic metabolism) on MRS. - The NAA peak is typically decreased or absent due to neuronal destruction and loss. *Meningioma* - **Meningiomas** are extra-axial tumors that originate from the meninges. On MRS, they typically show an elevated **alanine peak**, and sometimes elevated choline, but lack an elevated NAA peak. - Reduced or absent NAA is expected as these tumors are not composed of neuronal cells.

Q: On MRI, which of the following shows diffusion restriction?

Medulloblastoma. ***Medulloblastoma*** - **Medulloblastomas** are highly cellular tumors, leading to **restricted diffusion** on MRI due to the dense packing of cells and reduced extracellular space. - This feature helps distinguish them from other posterior fossa tumors like ependymomas and pilocytic astrocytomas. - They are the **most common malignant posterior fossa tumor in children** and show bright signal on DWI with low ADC values. *Ependymoma* - **Ependymomas** typically show **facilitated diffusion** or no significant diffusion restriction on MRI due to their less cellular nature and higher water content. - They often arise from the ependyma lining the ventricles and can have heterogeneous signal characteristics. - Variable ADC values are seen, generally higher than medulloblastomas. *Meningioma* - **Meningiomas** usually do not show significant **diffusion restriction**; instead, they have an appearance reflecting their fibrous and vascular nature. - They tend to be extra-axial, dural-based tumors that enhance homogenously. - ADC values are typically elevated compared to highly cellular tumors. *Germinoma* - **Germinomas** are also highly cellular tumors and **do show diffusion restriction** similar to medulloblastomas. - However, they are typically located in the **pineal or suprasellar regions**, not the posterior fossa. - In this context, **medulloblastoma** is the best answer as the classic example of a diffusion-restricting posterior fossa tumor commonly tested in examinations.

Q: Which of the following conditions is known to cause intracranial calcification visible on a skull X-ray?

Cysticercosis. ***Cysticercosis*** - **Cysticercosis**, caused by the larval stage of the **tapeworm *Taenia solium***, frequently leads to multiple parenchymal or subarachnoid cysts in the brain that often calcify after the larval death. - These calcified lesions are readily visible on skull X-rays and are a hallmark of chronic neurocysticercosis. *Pineal calcification (benign physiological process)* - **Pineal gland calcification** is a very common, often incidental finding that is considered a **normal physiological process** related to aging. - While visible on skull X-rays, it is typically of no clinical significance and not indicative of a disease state. *Dural calcification (associated with metabolic disorders)* - While **dural calcifications** can occur, they are generally rare and not a common or prominent cause of intracranial calcification visible on a skull X-ray in the context of a broadly asked question about conditions causing such findings. - When present, particularly extensive dural calcification, it can be associated with certain **metabolic disorders** (e.g., hyperparathyroidism) or genetic syndromes, but it is less frequently assessed via skull X-ray compared to other imaging modalities. *Tuberculosis (CNS involvement)* - **CNS tuberculosis** can lead to various manifestations, including **tuberculomas** and **tuberculous meningitis**. - While tuberculomas can rarely calcify, it is not as common or characteristic a feature on a skull X-ray as the calcifications seen in cysticercosis, and often requires more advanced imaging like CT or MRI for detailed visualization.

Q: Tram track appearance on a CT scan of the head is seen in which condition?

Sturge weber syndrome. ***Sturge Weber syndrome*** - The **'tram track' appearance** on a CT scan of the head is highly characteristic of Sturge-Weber syndrome. - This finding is due to **cortical gyriform calcifications** in the cerebral cortex, often associated with an underlying pial angioma. *Tuberous sclerosis* - Characterized by **subependymal nodules** and **cortical tubers**, which appear as calcified lesions on CT. - These calcifications typically do not present in a gyriform or 'tram track' pattern. *Neurofibromatosis* - This neurocutaneous syndrome has different characteristic imaging findings such as **optic gliomas**, **brainstem lesions**, and **plexiform neurofibromas**. - It does not present with cortical gyriform calcifications that would create a 'tram track' appearance on CT. *Von Hippel-Lindau syndrome* - This syndrome is associated with **hemangioblastomas** within the cerebellum, brainstem, spinal cord, and retina, as well as renal cysts and pheochromocytomas. - It does not present with cortical gyriform calcifications that would create a 'tram track' appearance on CT.

Q: Which primary brain parenchymal tumor is most commonly associated with calcifications seen on imaging studies?

Oligodendroglioma. ***Oligodendroglioma*** - **Oligodendrogliomas** are highly associated with **calcifications**, which are observed in **70-90% of cases** on imaging studies like CT scans. - The calcifications appear as **coarse, punctate, or nodular** and are typically located in the **cerebral hemispheres** (frontal and temporal lobes most common). - This is the **classic imaging finding** that helps differentiate oligodendrogliomas from other glial tumors. *Astrocytoma* - While some astrocytomas can calcify, especially low-grade forms, they are **not as consistently calcified** as oligodendrogliomas. - Calcifications occur in only **20-30% of cases** and are typically less prominent. *Medulloblastoma* - **Medulloblastomas** are most commonly found in the **cerebellum** (posterior fossa) and primarily affect children. - Calcifications are **infrequent**, occurring in approximately **10-20% of cases**, and are usually small and inconspicuous. *Craniopharyngioma* - **Craniopharyngiomas** are benign tumors arising from Rathke's pouch remnants, located in the **suprasellar region**. - While they do frequently calcify (especially in children), they are **extra-axial tumors**, not primary brain parenchymal tumors. - This question specifically asks about parenchymal brain tumors, making oligodendroglioma the correct answer among glial neoplasms.

Q: Primary investigation of choice in a patient with suspected subarachnoid hemorrhage should be:

Non-contrast computed tomography. ***Non-contrast computed tomography*** - **Non-contrast CT** of the head is the primary imaging modality for suspected subarachnoid hemorrhage due to its **rapid availability** and **high sensitivity** in detecting acute blood. - It effectively visualizes blood in the **subarachnoid space** as hyperdense areas, especially within the first 6-12 hours after symptom onset. *Magnetic resonance imaging (MRI)* - While MRI can detect subarachnoid hemorrhage, it is **less readily available** and takes longer to perform than CT in emergency settings. - MRI may be used in cases where CT is negative but suspicion remains high, especially for hemorrhage in the **posterior fossa** or older bleeds. *Contrast-enhanced computed tomography* - **Contrast-enhanced CT** is generally not the initial imaging choice for subarachnoid hemorrhage because fresh blood is highly visible on unenhanced scans. - Contrast administration can obscure the visualization of acute blood in the subarachnoid space and is typically reserved for **CT angiography** to identify the source of bleeding. *Lumbar puncture* - **Lumbar puncture** is performed if a non-contrast CT is negative for subarachnoid hemorrhage but clinical suspicion remains high. - Its purpose is to detect **xanthochromia** (yellow discoloration due to bilirubin from red blood cell breakdown) or an elevated red blood cell count, confirming the presence of blood in the cerebrospinal fluid.

Q: Which of the following conditions is most commonly associated with the "doughnut" sign seen on a brain scan?

Brain abscess. ***Brain abscess*** - The **doughnut sign**, characterized by a **ring-enhancing lesion** with a central hypodense core, is highly suggestive of a brain abscess due to central necrosis and peripheral inflammation. - The ring enhancement often appears **thinner and smoother** in abscesses compared to tumors, and there is usually significant surrounding edema. - This sign is most **characteristically and commonly associated** with pyogenic brain abscesses. *Brain metastases* - While brain metastases can also present as **ring-enhancing lesions**, they tend to have a **thicker and more irregular wall** compared to a brain abscess. - They often present with **multiple lesions** and a known primary malignancy, which differentiates them from a solitary abscess. *Glioblastoma multiforme* - **Glioblastoma multiforme (GBM)** typically shows a **thick, irregular, and often nodular ring enhancement** due to areas of necrosis, hypervascularity, and active tumor growth. - Its enhancing rim is generally **thicker and more variable** than that of a typical abscess, and it often invades surrounding brain parenchyma. *Toxoplasmosis* - **Cerebral toxoplasmosis** can present with ring-enhancing lesions, particularly in immunocompromised patients (HIV/AIDS). - Typically shows **multiple lesions** with predilection for basal ganglia and corticomedullary junction. - The "**eccentric target sign**" (eccentric dot within the ring) is more characteristic of toxoplasmosis than the smooth doughnut sign of pyogenic abscess.

Q: A patient with suspected subarachnoid haemorrhage presents with blood isolated in the fourth ventricle on a CT scan. Aneurysmal rupture is likely to have resulted from which of the following?

Basilar Artery Tip Aneurysm. ***Basilar Artery Tip Aneurysm*** - Aneurysmal rupture at the **basilar artery tip** can directly lead to bleeding into the **fourth ventricle** due to its anatomical proximity to the brainstem and ventricular system. - The basilar artery bifurcates at the tip into the posterior cerebral arteries, lying anterior to the pons and close to the floor of the fourth ventricle. *Posterior Inferior Cerebellar Artery Aneurysm* - Rupture of a **PICA aneurysm** typically causes bleeding in the cerebellopontine angle cistern or directly into the fourth ventricle, but is less common for isolated intraventricular hemorrhage compared to basilar tip. - PICA supplies the posterior inferior cerebellum and lower brainstem, and its rupture is more often associated with posterior fossa hemorrhage. *Anterior Communicating Artery Aneurysm* - Rupture of an **anterior communicating artery (ACOM) aneurysm** commonly results in **interhemispheric hemorrhage** and often causes blood in the lateral ventricles. - Due to its anterior location, it is anatomically unlikely to cause isolated bleeding in the **fourth ventricle**. *Posterior Communicating Artery Aneurysm* - Rupture of a **posterior communicating artery (PCOM) aneurysm** typically leads to subarachnoid hemorrhage around the **chiasmatic cisterns** and sylvian fissures. - While it is part of the posterior circulation, its rupture is less likely to result in isolated fourth ventricular hemorrhage compared to a basilar tip aneurysm.

Q: A middle-aged person is rushed to the emergency department with a history of loss of motor power in the left upper and lower limb since the last 30 minutes. The imaging modality of choice to plan appropriate treatment would be

CT scan of the head. ***CT scan of the head*** - A **non-contrast CT scan of the head** is the immediate imaging modality of choice in acute stroke symptoms to quickly rule out a **hemorrhagic stroke**. - This rapid assessment guides treatment decisions; if hemorrhage is absent, **thrombolytic therapy (tPA)** can be considered within the critical time window. *MRI of the brain* - While **MRI** offers superior detail for detecting ischemic stroke, it is **unsuitable for initial emergency assessment** due to longer acquisition times and limited availability. - The delay in obtaining an MRI could critically hinder the initiation of time-sensitive therapies like **thrombolysis**. *Carotid doppler study* - A **carotid Doppler study** is useful for identifying **carotid artery stenosis**, which can be a cause of ischemic stroke but is not an acute diagnostic tool for stroke itself. - It does not provide information about the presence of hemorrhage or acute ischemic changes within the brain parenchyma. *EEG* - An **EEG (electroencephalogram)** measures electrical activity in the brain and is primarily used to diagnose conditions like **seizures** or evaluate altered mental status. - It provides no structural information and is not indicated for the initial evaluation of acute motor deficits indicative of a stroke.

Q: CT scan of a child with intellectual disability who has recurrent seizures and a facial hemangioma. What is the diagnosis?

Encephalofacial angiomatosis. ***Encephalofacial angiomatosis*** - This condition, also known as **Sturge-Weber syndrome**, is characterized by a **facial port-wine stain (hemangioma)**, intellectual disability, and recurrent seizures due to **leptomeningeal angiomatosis** as seen in the CT image. - The CT scan shows characteristic unilateral **pial angiomatosis with underlying cortical calcifications**, often described as "tram-track" calcifications, representing the brain involvement. *Epiloias* - This is an older term for **tuberous sclerosis**, which presents with **facial angiofibromas** (not hemangioma), intellectual disability, and seizures. - CT scans in tuberous sclerosis typically show **subependymal nodules** and cortical tubers, not leptomeningeal angiomatosis with tram-track calcifications. *Louis Bar syndrome* - This is also known as **ataxia-telangiectasia**, a progressive neurodegenerative disease characterized by **cerebellar ataxia**, oculocutaneous telangiectasias, and immunodeficiency. - It does not present with hemangiomas or the specific CT findings of leptomeningeal angiomatosis and calcifications. *Neuronal ceroid lipofuscinoses* - This is a group of **lysosomal storage disorders** characterized by the accumulation of **lipopigment** in neurons and other cells, leading to progressive neurodegeneration. - Clinical features include progressive intellectual decline, seizures, and vision loss, but they are not associated with hemangiomas or the specific CT findings of Sturge-Weber syndrome.

Question 1

In which of the following diseases is the NAA peak seen?

Accepted Answer

Canavan disease

Answer

Tuberculoma

Answer

Meningioma

Answer

Glioblastoma

Question 2

On MRI, which of the following shows diffusion restriction?

Accepted Answer

Medulloblastoma

Answer

Ependymoma

Answer

Meningioma

Answer

Germinoma

Question 3

Which of the following conditions is known to cause intracranial calcification visible on a skull X-ray?

Accepted Answer

Cysticercosis

Answer

Dural calcification (associated with metabolic disorders)

Answer

Pineal calcification (benign physiological process)

Answer

Tuberculosis (CNS involvement)

Question 4

Tram track appearance on a CT scan of the head is seen in which condition?

Accepted Answer

Sturge weber syndrome

Answer

Tuberous sclerosis

Answer

Neurofibromatosis

Answer

Von Hippel-Lindau syndrome

Question 5

Which primary brain parenchymal tumor is most commonly associated with calcifications seen on imaging studies?

Accepted Answer

Oligodendroglioma

Answer

Astrocytoma

Answer

Medulloblastoma

Answer

Craniopharyngioma

Question 6

Primary investigation of choice in a patient with suspected subarachnoid hemorrhage should be:

Accepted Answer

Non-contrast computed tomography

Answer

Magnetic resonance imaging (MRI)

Answer

Contrast-enhanced computed tomography

Answer

Lumbar puncture

Question 7

Which of the following conditions is most commonly associated with the "doughnut" sign seen on a brain scan?

Accepted Answer

Brain abscess

Answer

Brain metastases

Answer

Glioblastoma multiforme

Answer

Toxoplasmosis

Question 8

A patient with suspected subarachnoid haemorrhage presents with blood isolated in the fourth ventricle on a CT scan. Aneurysmal rupture is likely to have resulted from which of the following?

Accepted Answer

Basilar Artery Tip Aneurysm

Answer

Posterior Inferior Cerebellar Artery Aneurysm

Answer

Anterior Communicating Artery Aneurysm

Answer

Posterior Communicating Artery Aneurysm

Question 9

A middle-aged person is rushed to the emergency department with a history of loss of motor power in the left upper and lower limb since the last 30 minutes. The imaging modality of choice to plan appropriate treatment would be

Accepted Answer

CT scan of the head

Answer

MRI of the brain

Answer

Carotid doppler study

Answer

EEG

Question 10

CT scan of a child with intellectual disability who has recurrent seizures and a facial hemangioma. What is the diagnosis?

Accepted Answer

Encephalofacial angiomatosis

Answer

Epiloias

Answer

Louis Bar syndrome

Answer

Neuronal ceroid lipofuscinoses

Neuroradiology — MCQs

Neuroradiology — MCQs

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